On 9 Sep 2006 06:31:57 -0400, linux@xxxxxxxxxxx <linux@xxxxxxxxxxx> wrote:
> If the out of order revisions are a small amount of the total then
> could be possible to have something like
>
> git rev-list --topo-order --with-appended-fixups HEAD
>
> Where, while git-rev-list is working _whithout sorting the whole tree
> first_, when finds an out of order revision stores it in a fixup-list
> buffer and *at the end* of normal git-rev-lsit the buffer is flushed
> to receiver, so that the drawing logic does not change and the out of
> order revisions arrive at the end, already packed, sorted and prepared
> by git-rev-list.
I don't think I understand your proposal. The problem arises when
git-rev-list finds a commit that it should have listed before something
that it has already output.
Just for example:
Commit D: Ancestor B
Commit B: Ancestor A
Commit C: Ancestor B
Commit C is the problem, because if git-rev-list has already output B,
there's no way to back up and insert it in the right place.
How is waiting to output the already-behind-schedule commit C going
to help anything?
It helps in a number of ways from receiver point of view.
- Receiver doesn't need to keep a sorted list of loaded revisions.
- Receiver doesn't need to stop parsing input and redraw the graph in
the middle of the loading.
- Receiver doesn't need to check for possible out of order commits
when loading data, but can be assured data that arrives is
--topo-order consistent (although my not be complete)
- Split the in order parsing code (performance critical and common
case) from fixup-code (run at the end and on a small set of commits).
- Much faster implementation because the sorting is done only in
git-rev-list and only once.
Following your example my suggestion was something like this:
Instead of:
git-rev-list HEAD
Commit D: Ancestor B
Commit B: Ancestor A
Commit C: Ancestor B
Commit A: Ancestor E
Commit E: Ancestor F
Commit F: Ancestor G
....
Commit V: Ancestor Z
git-rev-list --topo-order ----with-appended-fixups HEAD
sends something like:
Commit D: Ancestor B
Commit B: Ancestor A
Commit A: Ancestor E
Commit E: Ancestor F
Commit F: Ancestor G
....
Commit V: Ancestor Z
(* end of correct sorted commits and start of out of order commits*)
Commit C: Ancestor B
......
Commit N: Ancestor M
So that receiver drawing code designed with working with --topo-order
kind output could as usual draws the graph until Commit V: Ancestor Z
(but without waiting for git-rev-list latency!!) and the new fixup
code could *at the end* loop across *already sorted* fixup set:
Commit C: Ancestor B
......
Commit N: Ancestor M
and update the graph in one go. Of course some flag/syntax should be
introduced to trigger the end of sorted code and beginning of fixups
in git-rev-list output stream.
Marco
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